The price of a barrel of crude oil fell to near $30 first thing on Monday from $60 a few weeks ago, its single biggest daily drop since the 1991 Gulf war, after Saudi Arabia started a price war with Russia.

RAC fuel spokesperson, Simon Williams, said: “The last time we saw the wholesale price of petrol this low was in March 2016 which led to an average price of 106p a litre two weeks later. That’s nearly 17p a litre below the current average of 122.85p

“The diesel wholesale price was last this low in September 2016 which yielded a price of 113p a litre – 12.5p below its current UK average of 125.59p.

“It might be a bit too much to think we will see these prices again based on a one-day drop in the oil price but we ought to see at least 10p a litre coming off the price of unleaded in the next fortnight which would produce an average of 113p – a price last seen in October 2016.”

Retailers have been criticised in the past for not always passing on wholesale savings to customers.

Williams said: “We strongly urge every fuel retailer – large and small – to pass on these savings as soon as possible. But we expect the big supermarkets who sell the lion’s share of fuel to lead the way with some swift and significant cuts in the next few days.”

The latest oil price plunge came after Saudi Arabia slashed its export oil prices over the weekend sparking a price war with Russia.